Designing a stylish yet functional login form can be difficult, that's ignoring actually getting functionality behind the system in the first place. Here is a collection of screenshots of various login forms from popular web sites, along with some discussions about the methods being used.

Vertically or Horizontally?

Essentially it depends on your site design, sites such as Digg which include the login form in the header often choose a horizontal login form to compact the form in as little space as possible.

Digg use a horizontal login form which appears when the user selects the 'Login' link, interestingly this can provoke a warning from Internet security software which may not be ideal for compatibility.

Other sites which place the login form in the page body often choose the vertical approach.

MySpace uses a vertical login form which includes a 'Remember Me' option for returning visitors.

Remember Me?

Some sites include 'Remember Me' options enabling the login system to automatically remember and log the user in when they next visit. Sometimes this will simply mean the login system remembers the username, or some remember the password and entirely skip the login form.

Facebook's login form includes a 'Remember Me' option for returning visitors.

PayPal's login form does not include a 'Remember Me' option, this is clearly to avoid accidental security breaches.

Windows Live offers the choice, enabling the user to choose whether the system should remember their username, or their username and password.

The overal concensus seems to be a question of security, sites such as YouTube which do not store confidential data automatically remember the user for convenience. Sites such as PayPal where security is of major concern do not offer any option to remember login details and in fact, PayPal employs an extremely strict sessions system to avoid session hijacking.

Username or Email Address?

Should a login form request a username and password, or an email address and password? This is usually a question of preference and ultimately the best option is to give the user the choice. More secure login systems, such as online banking login systems require the user enter only selected characters from their password. This is a fantastic security method which prevents key loggers from being used to gather login details, or from malicious individuals from monitoring internet connections to collect the details.

Natwest's Online Banking system requires you enter three characters from your password and pin code, the required characters are chosen at random. This of course only reduces the risk of occassional key logging, if someone were to continually monitor the same user for an extended period of time they could gather the login credentials in the same way, but this login method does offer protection for the user when using insecure computers on occassion.